1. Field of the Invention
This invention relates to apparatus for offset stacking copy sheet sets in a receptacle.
2. Description of the Prior Art
It is desirable to provide offset copy sheet sets at the output of a copy processing device such as an electrographic copier. For example, U.S. Pat. No. 3,630,607 discloses a document handling apparatus which recirculates the pages of a document to an exposure platen of a xerographic copier which produces copy sheets corresponding to these pages. This apparatus further includes a copy set finisher for assembling the copy sheets into sets in an intermediate tray assembly, and a device for ejecting the sets into an output tray where they are stacked in a staggered, i.e., offset manner. U.S. Pat. Nos. 3,671,094, 3,682,328, 3,685,712, 3,690,537 and 3,709,595 disclose apparatus including a recirculating document feeder, xerographic copier and a copy finisher. These apparatus either assemble copy sheets into booklets for stapling in an intermediate tray before straight stacking the stapled booklets in an output tray or by means of a paddle wheel mechanism, cause individual copy sheets to by-pass the intermediate tray and to be individually offset stacked in sets in the output tray.
Although the various offset stacking devices disclosed in the aforementioned patents may be appropriate for their intended uses, they are all relatively complex and on occasion suffer from problems such as paper jamming and misfeeds.
The present invention is concerned with selectively applying different velocity profiles to copy sheets to cause them to be delivered into offset stacks of copy sheet sets in a receiving receptacle. U.S. Pat. No. 3,929,327 discloses a drive roller or conical configuration which aligns copy sheets. It does not disclose or even mention offset stacking of copy sheet sets. U.S. Pat. No. 3,175,824 depicts frusto-conical or beveled gear rollers which skew sheets but do not offset stack copy sheet sets. In the paper box art, machines are well-known which provide for turning and also for stacking carton blanks. See for example, U.S. Pat. Nos. 2,761,363 and 3,758,104.